Question 9.44: Briefly explain integrated injection logic....
Briefly explain integrated injection logic.
In this system Q_{1} and Q_{3} act as current sources to the bases of Q_{2} and Q_{4}, respectively. If input A goes LOW, the current to the base of Q_{2} will be shorted to ground, preventing the transistor from conducting. In a similar manner, input B controls Q_{4}. Thus, if either point A OR B is HIGH, the output will be LOW, a NOR function.
The collector of Q_{1} is made of the same material as the base of Q_{2}, making it possible to be the same physical elements. This greatly improves the density that a given chip can contain. There are no resistors, further reducing the size of the gate. Therefore, \mathrm{I}^{2} \mathrm{~L} is used in large scale functions, where bipolar devices are required. It is slightly faster (10 ns) than TTL.
